Figure 6.

Anaerobic limited trypsinolysis of (A) wild type, (B) H49A, and (C) H299N in the absence (left) and presence (right) of MAP over time. Full length DXP synthase (one asterisk), cleavage product 1 (44 kDa, two asterisks, cleavage at K227), and cleavage product 2 (34 kDa, three asterisks, cleavage at K313) are indicated. (D) Closed model of E. coli DXP synthase.¹⁸ The positions of the two major trypsin cleavage sites as well at His49, His299, and ThDP are shown as sticks colored by element. The three flexible regions observed by HDX-MS are colored blue (residues 42–58), green (residues 182–199), and pink (residues 278–298).¹⁸